This invention relates to roller doors of the kind comprising a semi-rigid curtain able to be wrapped upon a drum structure extending above a doorway and to be unwrapped from that drum structure to constitute a closure for the doorway. More particularly, the invention relates to electrically driven roller doors of the above-mentioned kind.
In the past, if the curtain of an electrically driven roller door should strike an object lying in its path as the door is closing, substantial damage is likely to occur to the door assembly and drive means as well as to the object struck. The latter is especially significant when the object struck is a person.
An object of the present invention is to overcome the above indicated disadvantage by providing in an electrically driven roller door switching means on the bottom edge of the door curtain which extend substantially the width of the curtain, in combination with a drive motor control device to reverse the downward travel of the curtain when an object is struck.